Insect reproduction is under endocrine control but little is known about this process in holometabalous long-lived insect species. Our model is the mealworm beetle and we are charting the differentiation and maturation of the accessory glands of the male. In the coming year we will be refining our ultrastructural and electrophoretic indices for staging differentiation in the larva, pupa, and adult. We can support the differentiation of these glands in vivo (by transplantation) and a series of synchronous and asynchronous in vivo experiments will be continued. Some stages will differentiate in vitro without addition of any hormones indicating that their differentiation is time not signal dependent. Others do not develop in vitro suggesting that hormones must be added to allow maturation. We will utilize replacement therapy in our culture systems to ask which hormones are necessary and at what points. As these studies progress we will investigate the effects of hormones on patterns of RNA synthesis and upon translation of the messenger RNA populations. This model is useful for general studies for cell differentiation, studies of hormone action, and may provide insight into the way that the reproductive physiology of long-lived insect disease vectors and agricultural pests can be manipulated so that the insect population can be controlled.